Optical member and display device including the same

ABSTRACT

An optical member and a display device including the same. The optical member includes a light guide plate including a surface disposed on a plane defined by a first direction and a second direction crossing the first direction, a low refractive index pattern disposed on the surface of the light guide plate and including an opening for exposing the surface of the light guide plate, a wavelength conversion layer disposed on the low refractive index pattern, and a passivation layer disposed on the wavelength conversion layer and covering a side surface of the wavelength conversion layer and a side surface of the low refractive index pattern at least one side portion. The low refractive index pattern has a lower index of refraction than the light guide plate, and a ratio of an area occupied by the low refractive index pattern to an area of the surface of the light guide plate decreases in the first direction.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a Continuation of U.S. patent application Ser. No.16/503,195, filed Jul. 3, 2019, which is a Continuation of U.S. patentapplication Ser. No. 16/111,215, filed Aug. 24, 2018, issued as U.S.Pat. No. 10,371,881, and claims priority from and the benefit of KoreanPatent Application No. 10-2017-0115283, filed on Sep. 8, 2017, each ofwhich is hereby incorporated by reference for all purposes as if fullyset forth herein.

BACKGROUND Field

Exemplary embodiments of the inventive concepts relate to an opticalmember and a display device including the same.

Discussion of the Background

A liquid crystal display device receives light from a backlight assemblyand displays an image. Some backlight assemblies include a light sourceand a light guide plate. A light guide plate receives light from a lightsource and guides the light in a propagation direction toward a displaypanel. Some products have a light source for providing white light andrepresent colors by filtering the white light with a color filterincluded in a display panel.

Recently, research has been conducted on the application of a wavelengthconversion film to improve image quality such as color reproducibilityof a liquid crystal display device. Typically, a blue light source isused as a light source and a wavelength conversion file is disposed on alight guide plate to convert blue light into a white color. Thewavelength conversion film includes wavelength conversion particles, andthe wavelength conversion particles are generally vulnerable tomoisture, and thus, are protected by a barrier film. However, a barrierfilm is expensive and may cause an increase in thickness. Further, sincea wavelength conversion film should be stacked on a light guide plate, acomplicated assembly process may be required.

The above information disclosed in this Background section is only forunderstanding of the background of the inventive concepts, and,therefore, it may contain information that does not constitute priorart.

SUMMARY

Exemplary embodiments of the inventive concepts provide an opticalmember having a light guide function and a sealed wavelength conversionlayer.

Exemplary embodiments of the inventive concepts also provide a displaydevice including an optical member having a light guide function and asealed wavelength conversion layer.

Additional features of the inventive concepts will be set forth in thedescription which follows, and in part will be apparent from thedescription, or may be learned by practice of the inventive concepts.

An exemplary embodiment discloses an optical member including a lightguide plate including a surface disposed on a plane defined by a firstdirection and a second direction crossing the first direction, a lowrefractive index pattern disposed on the surface of the light guideplate and including an opening for exposing the surface of the lightguide plate, a wavelength conversion layer disposed on the lowrefractive index pattern, and a passivation layer disposed on thewavelength conversion layer and configured to cover a side surface ofthe wavelength conversion layer and a side surface of the low refractiveindex pattern at at least one side portion. The low refractive indexpattern has a lower index of refraction than the light guide plate, anda ratio of an area occupied by the low refractive index pattern to anarea of the surface of the light guide plate decreases in the firstdirection.

An exemplary embodiment also discloses an optical member including alight guide plate including a surface, a first side surface crossing thesurface, and a second surface opposite the first side surface, a lowrefractive index pattern disposed on the surface of the light guideplate and including an opening for exposing the surface of the lightguide plate, a wavelength conversion layer disposed on the lowrefractive index pattern, and a passivation layer disposed on thewavelength conversion layer and configured to cover a side surface ofthe wavelength conversion layer and a side surface of the low refractiveindex pattern at at least one side portion. The low refractive indexpattern has a lower index of refraction than the light guide plate, anda ratio of an area occupied by the low refractive index pattern to anarea of the surface of the light guide plate decreases in a directionaway from the first side surface.

An exemplary embodiment also discloses a display device including anoptical member including a light guide plate including a light incidencesurface, a low refractive index layer disposed on the light guide plateand having a lower index of refraction than the light guide plate, awavelength conversion layer disposed on the low refractive index layer,and a passivation layer disposed on the wavelength conversion layer andconfigured to cover a side surface of the wavelength conversion layerand a side surface of the low refractive index layer at at least oneside portion, a light source disposed at a side of the light incidencesurface of the light guide plate, and a display panel disposed on theoptical member. An area in which the low refractive index layer isdisposed decreases in a direction away from the light incidence surface.

It is to be understood that both the foregoing general description andthe following detailed description are exemplary and explanatory and areintended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate exemplary embodiments of theinvention, and together with the description serve to explain theinventive concepts.

FIG. 1 is a perspective view of an optical member and a light sourceaccording to an exemplary embodiment.

FIG. 2 is an exploded perspective view of an optical member according toan exemplary embodiment.

FIG. 3 is a sectional view taken along line of FIG. 1.

FIG. 4 and FIG. 5 are sectional views of a low refractive index patternaccording to various exemplary embodiments.

FIG. 6, FIG. 7, FIG. 8 and FIG. 9 are plan views showing a light guideplate on which a low refractive index pattern is disposed according tovarious exemplary embodiments.

FIG. 10, FIG. 11, and FIG. 12 are sectional views schematically showinga method of manufacturing a low refractive index pattern according to anexemplary embodiment.

FIG. 13 is a sectional view schematically showing a method ofmanufacturing a low refractive index pattern according to anotherexemplary embodiment.

FIG. 14, FIG. 15, FIG. 16, and FIG. 17 are sectional views of opticalmembers according to still other exemplary embodiments.

FIG. 18 is a sectional view of an optical member according to stillanother exemplary embodiment.

FIG. 19 is a sectional view of an optical member according to stillanother exemplary embodiment.

FIG. 20 and FIG. 21 are sectional views of optical members according tostill other exemplary embodiments.

FIG. 22 and FIG. 23 are sectional views of optical members according tostill another exemplary embodiment.

FIG. 24 is a sectional view of a display device according to anexemplary embodiment.

FIG. 25 is a sectional view of an optical film according to an exemplaryembodiment.

FIG. 26 is a sectional view of a display device according to anotherexemplary embodiment.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various exemplary embodiments of the invention. As usedherein, “embodiments” are non-limiting examples of devices or methodsemploying one or more of the inventive concepts disclosed herein. It isapparent, however, that various exemplary embodiments may be practicedwithout these specific details or with one or more equivalentarrangements. In other instances, well-known structures and devices areshown in block diagram form in order to avoid unnecessarily obscuringvarious exemplary embodiments. Further, various exemplary embodimentsmay be different, but do not have to be exclusive. For example, specificshapes, configurations, and characteristics of an exemplary embodimentmay be used or implemented in another exemplary embodiment withoutdeparting from the inventive concepts.

Unless otherwise specified, the illustrated exemplary embodiments are tobe understood as providing exemplary features of varying detail of someways in which the inventive concepts may be implemented in practice.Therefore, unless otherwise specified, the features, components,modules, layers, films, panels, regions, and/or aspects, etc.(hereinafter individually or collectively referred to as “elements”), ofthe various embodiments may be otherwise combined, separated,interchanged, and/or rearranged without departing from the inventiveconcepts.

The use of cross-hatching and/or shading in the accompanying drawings isgenerally provided to clarify boundaries between adjacent elements. Assuch, neither the presence nor the absence of cross-hatching or shadingconveys or indicates any preference or requirement for particularmaterials, material properties, dimensions, proportions, commonalitiesbetween illustrated elements, and/or any other characteristic,attribute, property, etc., of the elements, unless specified. Further,in the accompanying drawings, the size and relative sizes of elementsmay be exaggerated for clarity and/or descriptive purposes. When anexemplary embodiment may be implemented differently, a specific processorder may be performed differently from the described order. Forexample, two consecutively described processes may be performedsubstantially at the same time or performed in an order opposite to thedescribed order. Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,”“connected to,” or “coupled to” another element or layer, it may bedirectly on, connected to, or coupled to the other element or layer orintervening elements or layers may be present. When, however, an elementor layer is referred to as being “directly on,” “directly connected to,”or “directly coupled to” another element or layer, there are nointervening elements or layers present. To this end, the term“connected” may refer to physical, electrical, and/or fluid connection,with or without intervening elements. For the purposes of thisdisclosure, “at least one of X, Y, and Z” and “at least one selectedfrom the group consisting of X, Y, and Z” may be construed as X only, Yonly, Z only, or any combination of two or more of X, Y, and Z, such as,for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

Although the terms “first,” “second,” etc. may be used herein todescribe various types of elements, these elements should not be limitedby these terms. These terms are used to distinguish one element fromanother element. Thus, a first element discussed below could be termed asecond element without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,”“above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), andthe like, may be used herein for descriptive purposes, and, thereby, todescribe one elements relationship to another element(s) as illustratedin the drawings. Spatially relative terms are intended to encompassdifferent orientations of an apparatus in use, operation, and/ormanufacture in addition to the orientation depicted in the drawings. Forexample, if the apparatus in the drawings is turned over, elementsdescribed as “below” or “beneath” other elements or features would thenbe oriented “above” the other elements or features. Thus, the exemplaryterm “below” can encompass both an orientation of above and below.Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90degrees or at other orientations), and, as such, the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing particularembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. It is also noted that, as used herein, the terms“substantially,” “about,” and other similar terms, are used as terms ofapproximation and not as terms of degree, and, as such, are utilized toaccount for inherent deviations in measured, calculated, and/or providedvalues that would be recognized by one of ordinary skill in the art.

Various exemplary embodiments are described herein with reference tosectional and/or exploded illustrations that are schematic illustrationsof idealized exemplary embodiments and/or intermediate structures. Assuch, variations from the shapes of the illustrations as a result, forexample, of manufacturing techniques and/or tolerances, are to beexpected. Thus, exemplary embodiments disclosed herein should notnecessarily be construed as limited to the particular illustrated shapesof regions, but are to include deviations in shapes that result from,for instance, manufacturing. In this manner, regions illustrated in thedrawings may be schematic in nature and the shapes of these regions maynot reflect actual shapes of regions of a device and, as such, are notnecessarily intended to be limiting.

Advantages and features of the present disclosure and methods ofaccomplishing the same may be understood more readily by reference tothe following detailed description of exemplary embodiments and theaccompanying drawings. The present disclosure may, however, be embodiedin many different forms and should not be construed as being limited tothe exemplary embodiments set forth herein. Rather, these exemplaryembodiments are provided so that this disclosure will be thorough andcomplete and will fully convey the concept of the present disclosure tothose skilled in the art, and the present disclosure will only bedefined within the scope of the appended claims.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another element. Thus, a first element discussed belowcould be termed a second element without departing from the teachings ofthe present invention

Hereinafter, exemplary embodiments will be described with reference tothe accompanying drawings.

FIG. 1 is a perspective view of an optical member and a light sourceaccording to an exemplary embodiment. FIG. 2 is an exploded perspectiveview of an optical member according to an exemplary embodiment. FIG. 3is a sectional view taken along line of FIG. 1.

Referring to FIGS. 1 to 3, an optical member 100 includes a light guideplate 10, a low refractive index pattern 20 disposed on the light guideplate 10, and a wavelength conversion layer 30 disposed on the lowrefractive index pattern 20, and a passivation layer 40 disposed on thewavelength conversion layer 30. The light guide plate 10, the lowrefractive index pattern 20, the wavelength conversion layer 30, and thepassivation layer 40 may be integrated and combined.

The light guide plate 10 serves to guide a light propagation path.Generally, the light guide plate 10 may have a polygonal prism shape. Aplanar shape of the light guide plate 10 may be a rectangle having twoshort sides disposed in a first direction X and two long sides disposedin a second direction Y, but the inventive concepts are not limitedthereto. For example, the light guide plate 10 may have a quadrangularprism shape including a rectangle as the planar shape, and may includean upper surface 10 a, a lower surface 10 b, and four side surfaces 10S(10S1, 10S2, 10S3, and 10S4). In this specification and the accompanyingdrawings, the reference symbols “10S1,” “10S2,” “10S3,” and “10S4” areused to distinguish the four side surfaces, and the reference symbol“10S” is used to simply refer to one side surface.

For example, the upper surface 10 a and the lower surface 10 b of thelight guide plate 10 may be located on a plane defined by the firstdirection X and the second direction Y, and the light guide plate 10 mayhave an entirely uniform thickness. However, the inventive concepts arenot limited thereto, the upper surface 10 a or the lower surface 10 bmay be composed of a plurality of planes, and a plane on which the uppersurface 10 a is located and a plane on which the lower surface 10 b islocated may intersect. For example, the light guide plate 10 may have athickness decreasing from a first side surface (e.g., a light incidencesurface) to a second side surface opposite the first side surface (e.g.,an opposite surface) like a wedge-type light guide plate. Also, thelight guide plate 10 may be formed to have a shape in which the lowersurface 10 b is upwardly inclined near the first surface (e.g., thelight incidence surface) up to a specific point so that the uppersurface 10 a and the lower surface 10 b become flat and then thethickness decreases toward the second side surface (e.g., the oppositesurface) opposite the first side surface.

The plane on which the upper surface 10 a and/or the lower surface 10 bare located may be inclined at about 90 degrees with respect to theplane on which the side surface 10S is located. However, the inventiveconcepts are not limited thereto, and an inclined corner may be furtherincluded between the upper surface 10 a and the side surface 10S and/orbetween the lower surface 10 b and the side surface 10S.

As an application of the optical member 100, a light source 400 may bedisposed adjacent to at least one side surface 10S of the light guideplate 10. In the drawings, a plurality of LED light sources 410 mountedon a printed circuit board 420 are disposed at the side surface 10S1located at one long side of the light guide plate 10, but are notlimited thereto. For example, the plurality of LED light sources 410 maybe disposed adjacent to each other at the side surfaces 10S1 and 10S3 ofboth the long sides or may be disposed adjacent to each other at theside surfaces 10S2 and 10S4 of one or both of the short sides. In theexemplary embodiment of FIG. 1, the side surface 10S1 of one long sideof the light guide plate 10 at which the LED light sources 410 aredisposed adjacent to each other is defined as a light incidence surface(depicted as “10S1” herein for convenience of description) on whichlight of the light source 400 is directly incident, and the side surface10S1 of the other long side of the light guide plate 10 opposite the oneside is defined as an opposite surface (depicted as “10S3” herein forconvenience of description).

The light guide plate 10 may include an inorganic material. For example,the light guide plate 10 may be made of glass, but is not limitedthereto.

The low refractive index pattern 20 is disposed on the upper surface 10a of the light guide plate 10. The low refractive index pattern 20 maybe directly formed on the upper surface 10 a of the light guide plate 10to be in contact therewith. The upper surface 10 a of the light guideplate 10 at which the low refractive index pattern 20 is not disposed isexposed to the wavelength conversion layer 30. That is, the uppersurface 10 a of the light guide plate 10 at which the low refractiveindex pattern 20 is not disposed may be in contact with the wavelengthconversion layer 30. Sufficient total reflection may occur on the uppersurface 10 a of the light guide plate 10 in contact with the lowrefractive index pattern 20.

In more detail, effective internal total reflection should occur on theupper surface 10 a and the lower surface 10 b of the light guide plate10 in order to perform efficient light guiding from the light incidencesurface 10S1 to the opposite surface 10S3 by the light guide plate 10.One condition for the internal total reflection occurring in the lightguide plate 10 is that the light guide plate 10 has a greater refractiveindex than a medium forming an optical interface with the light guideplate 10. As the refractive index of the medium forming the opticalinterface with the light guide plate 10 decreases, the internal totalreflection may increase due to a decrease in a critical angle for totalreflection.

The case in which the light guide plate 10 is formed of glass having arefractive index of about 1.5 will be described as an example. In thiscase, the wavelength conversion layer 30 stacked on the upper surface 10a of the light guide plate 10 typically has a refractive index of about1.5. When the wavelength conversion layer 30 is directly stacked on theupper surface 10 a of the light guide plate 10, it is difficult forsufficient total reflection to occur on the upper surface 10 a of thelight guide plate 10. Light L1 incident on an optical interface formedbetween the wavelength conversion layer 30 and the light guide plate 10is not totally reflected, but is instead emitted through the uppersurface 10 a of the light guide plate 10. On the other hand, the lowrefractive index pattern 20 forming an interface with the upper surface10 a of the light guide plate 10 has a lower index of refraction thanthe light guide plate 10, and thus, total reflection occurs in a regionin which the low refractive index pattern 20 is disposed. That is, lightL2 incident on an optical interface formed between the low refractiveindex pattern 20 and the light guide plate 10 is totally reflected totravel toward the opposite surface 10S3. Total reflection occurs at arelatively high rate in a region in which the light guide plate 10 andthe low refractive index pattern 20 are in direct contact with eachother, and occurs at a relatively low rate in a region in which thelight guide plate 10 and the wavelength conversion layer 30 are indirect contact with each other. In this regard, it is possible toincrease total reflection efficiency by increasing an area occupied bythe low refractive index pattern 20 such that total reflection may occurat a relatively high rate. For example, a ratio of the area occupied bythe low refractive index pattern 20 to the upper surface 10 a of thelight guide plate 10 may be high near the light incidence surface 10S1having a more sufficient amount of light than the opposite surface 10S3.

In detail, light from the light source 400 is directly incident on anarea adjacent to the light incidence surface 10S1 of the light guideplate 10, and thus, there is a sufficient amount of guided light. On theother hand, in an area adjacent to the opposite surface 10S3 of thelight guide plate 10, most of the light travels by total reflection inthe light guide plate 10, and there is a smaller amount of guided lightthan that of the light incidence surface 10S1. Thus, the amount of lightentering the upper surface 10 a of the light guide plate 10 isrelatively large near the light incidence surface 10S1, and the amountof light entering the upper surface 10 a of the light guide plate 10 isrelatively lacking near the opposite surface 10S3. When the lowrefractive index pattern 20 is disposed on the entirety of the uppersurface 10 a of the light guide plate 10 at the same area ratio per unitarea, the amount of light emitted through the upper surface 10 a of thelight guide plate 10 near the light incidence surface 10S1 may begreater than the amount of light emitted near the opposite surface 10S2.In this case, in terms of a display surface, a luminance non-uniformityphenomenon may occur, in which a region in which the light source 400 isdisposed is recognized as being relatively bright. It is possible toimprove brightness uniformity by adjusting a direct contact ratiobetween the low refractive index pattern 20 and the light guide plate 10depending on the amount of light guided in the light guide plate 10.

In detail, near the light incidence surface 10S1 in which the amount oflight guided in the light guide plate 10 is sufficient, the amount oftotally reflected light is increased by increasing the area of the uppersurface 10 a of the light guide plate 10 occupied by the low refractiveindex pattern 20 over the area of the upper surface 10 a of the lightguide plate 10 occupied by the wavelength conversion layer 30. On theother hand, near the opposite surface 10S3 in which the amount of lightguided in the light guide plate 10 is small, the area occupied by thelow refractive index pattern 20 is decreased, and the region in whichthe light guide plate 10 and the wavelength conversion layer 30 are indirect contact with each other is increased. In the region in which thewavelength conversion layer 30 and the light guide plate 10 are incontact with each other, light is not totally reflected but is emittedthrough the upper surface 10 a of the light guide plate 10. As a result,the amount of emitted light is small compared to the amount of guidedlight near the light incidence surface 10S1 and the amount of emittedlight is large compared to the amount of guided light near the oppositesurface 10S3, and thus, the amount of light emitted through the entiretyof the upper surface 10 a of the light guide plate 10 is uniform. Sincelight is uniformly emitted from the upper surface 10 a of the lightguide plate 10, luminance uniformity can be improved.

The luminance uniformity may be improved by forming a scattering pattern(not shown) having a different arrangement density on the lower surface10 b of the light guide plate 10. In this case, however, costs mayincrease due to a process of forming the scattering pattern, and also itmay be difficult to sufficiently reduce the thickness of the displaydevice because a thickness of the optical member 100 is increased by thescattering pattern. On the other hand, it is possible to enable processsimplification and maintain a reduced thickness of the optical member100 when the luminance uniformity is improved by adjusting the ratio ofdirect contact between the low refractive index pattern 20 and the lightguide plate 10 depending on the amount of light guided in the lightguide plate 10. The shape of the low refractive index pattern 20 will bedescribed in detail below.

The refractive index of the light guide plate 10 and the refractiveindex of the low refractive index pattern 20 may have a difference of0.2 or more. When the refractive index of the low refractive indexpattern 20 is lower than the refractive index of the light guide plate10 by 0.2 or more, sufficient total reflection may occur through theupper surface 10 a of the light guide plate 10. A maximum differencebetween the refractive index of the light guide plate 10 and therefractive index of the low refractive index pattern 20 is notparticularly limited. However, the maximum difference may be less thanor equal to 1 in consideration of the material of the light guide plate10 and the refractive index of the low refractive index pattern 20 whichare typically applied.

The refractive index of the low refractive index pattern 20 may rangefrom 1.2 to 1.4, and preferably from 1.2 to 1.3. Generally, as a solidmedium is manufactured to have a refractive index closer to 1, amanufacturing cost thereof exponentially increases. When the refractiveindex of the low refractive index pattern 20 is greater than or equal to1.2, it is possible to prevent an excessive increase in themanufacturing cost. Also, when the refractive index of the lowrefractive index pattern 20 is less than or equal to 1.4, it isadvantageous for sufficiently reducing a critical angle for totalreflection of the upper surface 10 a of the light guide plate 10. Whenthe refractive index of the low refractive index pattern 20 is less thanor equal to 1.3, the difference between the refractive index of the lowrefractive index pattern 20 and the refractive index of the light guideplate 10 further increases, and thus, the critical angle for totalreflection of the upper surface 10 a of the light guide plate 10 furtherdecreases. Thus, it is possible for total reflection to more effectivelyoccur through the upper surface 10 a of the light guide plate 10.

For example, the low refractive index pattern 20 having a refractiveindex of about 1.25 may be applied.

The low refractive index pattern 20 may include a void in order to havethe above-described low refractive index. The void may be made to be ina vacuum or filled with an air layer, gas, or the like. A space of thevoid may be defined by a particle, a matrix, or the like. This will bedescribed in detail with reference to FIGS. 4 and 5.

FIGS. 4 and 5 are sectional views of a low refractive index patternaccording to various exemplary embodiments.

In an exemplary embodiment, the low refractive index pattern 20 mayinclude a plurality of particles PT, a matrix MX formed as one body andconfigured to surround the particles PT, and a void VD, as shown in FIG.4. Each of the particles PT may be a filler configured to adjust arefractive index and a mechanical intensity of the low refractive indexpattern 20.

In the low refractive index pattern 20, the particles PT may bedispersed in the matrix MX, the matrix MX may be partially open, and thevoid VD may be formed at a corresponding portion. For example, the voidVD may be formed in the matrix MX by mixing the plurality of particlesPT and the matrix MX with a solvent, drying and/or curing the mixture,and vaporizing the solvent.

In another exemplary embodiment, the low refractive index pattern 20 mayinclude the matrix MX and the void VD without particles, as shown inFIG. 5. For example, the low refractive index pattern 20 may include thematrix MX formed as one body, such as a foam resin, and a plurality ofvoids VDs disposed in the matrix MX.

As shown in FIGS. 4 and 5, when the low refractive index pattern 20includes the void VD, the total refractive index of the low refractiveindex pattern 20 may range between a refractive index of the particlePT/matrix MX and a refractive index of the void VD. As described above,in the case in which the void VD is in vacuum having a refractive indexof 1 or is filled with an air layer or gas having a refractive index ofabout 1, the total refractive index of the low refractive index pattern20 may be less than or equal to 1.4, for example, 1.25, even when amaterial having a refractive index of 1.4 or more is used as theparticle PT/the matrix MX. For example, the particle PT may be made ofan inorganic material, such as SiO2, Fe₂O₃, and MgF₂, and the matrix MXmay be made of an organic material, such as polysiloxane. Alternatively,other organic or inorganic materials may be used.

Referring back to FIGS. 1 to 3, the low refractive index pattern 20 mayhave a thickness ranging from 0.4 μm to 2 μm. When the thickness of thelow refractive index pattern 20 is greater than or equal to 0.4 μm,which is in visible light wavelength range, an effective opticalinterface may be formed with the upper surface 10 a of the light guideplate 10, and thus, total reflection is more likely to occur on theupper surface 10 a of the light guide plate 10, according to Snell'slaw. The low refractive index pattern 20 that is too thick may becontrary to thinning the optical member 100, may increase materialcosts, and may be disadvantageous in terms of luminance of the opticalmember 100, and thus, the low refractive index pattern 20 may be formedto have a thickness of 2 μm or less. For example, the thickness of thelow refractive index pattern 20 may be about 0.5 μm.

As described above, the ratio of the area occupied by the low refractiveindex pattern 20 to the upper surface 10 a of the light guide plate 10may change depending on the amount of light guided into the light guideplate 10.

For example, the low refractive index pattern 20 may adjust the ratio ofthe area occupied by the low refractive index pattern 20 per unit areaby including through-holes H1 having different sizes and/or positions.

In another example, the low refractive index pattern 20 may include aplurality of low refractive index patterns 22, 23, and 24, as shown inFIGS. 7 to 9. Ratios of the areas occupied by the low refractive indexpatterns 22, 23, and 24 per unit area may be adjusted by changing sizesand/or positions of the low refractive index patterns 22, 23, and 24.The case in which the plurality of low refractive index patterns 22, 23,and 24 are disposed will be described with reference to FIGS. 7 to 9.The case in which the through-hole H1 is formed on the low refractiveindex pattern 20 will be described below.

The low refractive index pattern 20 may cover most of the upper surface10 a of the light guide plate 10 and may expose a portion of an edge ofthe light guide plate 10. In other words, the side surface 10S of thelight guide plate 10 may protrude relative to a side surface 20 s of thelow refractive index pattern 20. The upper surface 10 a exposed by thelow refractive index pattern 20 provides a space in which the sidesurface 20 s of the low refractive index pattern 20 may be stablycovered by the passivation layer 40.

The through-hole H1 passes through the low refractive index pattern 20from an upper surface 20 a of the low refractive index pattern 20 to alower surface 20 b thereof, that is, in a third direction Z. The uppersurface 10 a of the light guide plate 10 is exposed in a region in whichthe through-hole H1 is disposed. The wavelength conversion layer 30 isdisposed in the through-hole H1, and the upper surface 10 a of the lightguide plate 10 exposed by the through-hole H1 may be in direct contactwith the wavelength conversion layer 30.

A planar shape of the through-hole H1 is not particularly limited andmay be a circular shape, as shown in FIG. 2. In this specification, theplanar shape of the through-hole H1 refers to a sectional shape of thethrough-hole H1 taken vertically in the third direction Z.

The planar area of the through-hole H1 may be substantially uniformalong positions in the third direction Z. In this specification, theplanar area of the through-hole H1 refers to an area of a figure havinga shape corresponding to the planar shape of the through-hole H1. Forexample, when the planar shape of the through-hole H1 is circular, aninner wall of the through-hole H1 is substantially perpendicular to anyone surface of the low refractive index pattern 20, and the through-holeH1 may have a cylindrical shape as a whole.

The through-holes H1 may be regularly arranged in the first direction Xand the second direction Y. For example, the through-holes H1 may bearranged at regular intervals in the first direction X and the seconddirection Y. That is, the through-holes H1 may be substantially disposedin the shape of a matrix. As another example, the through-holes H1 maybe arranged at regular intervals in the second direction Y, and aseparation distance between the through-holes H1 may gradually decreasein the first direction X. In this case, in a sectional shape taken inthe first direction X, a width of the low refractive index pattern 20may gradually decrease. However, the separation distance between thethrough-holes H1 is not limited to the above example. Also, thethrough-holes H1 may be irregularly arranged in the first direction Xand/or the second direction Y. Even in this case, the through-holes H1are arranged in consideration of the ratio of the area occupied by thelow refractive index pattern 20 per unit area.

A diameter d of the through-hole H1 may gradually increase in the firstdirection X. That is, the planar area of the through-hole H1 maygradually increase in the first direction X. Thus, an area occupied bythe low refractive index pattern 20 in the upper surface 10 a of thelight guide plate 10 may gradually decrease in the first direction X.For example, when the separation distance between the through-holes H1is uniform in the first direction X, the width of the low refractiveindex pattern 20 disposed between the through-holes H1 may be constant.Nevertheless, the diameter d of the through-hole H1 increases in thefirst direction X, and thus the separation distance in the lowrefractive index pattern 20 increases. Accordingly, a ratio of the areaoccupied by the low refractive index pattern 20 per unit area near thelight incidence surface 10S1 may be higher than a ratio of the areaoccupied by the low refractive index pattern 20 per unit area near theopposite surface 10S3.

The wavelength conversion layer 30 is disposed in the through-hole H1,and the upper surface 10 a of the light guide plate 10 exposed by thethrough-hole H1 may be in direct contact with the wavelength conversionlayer 30. As an area of the through-hole H1 increases in the firstdirection X, the area of the upper surface 10 a of the light guide plate10 in direct contact with the wavelength conversion layer 30 mayincrease. An area occupied by the low refractive index pattern 20 in theupper surface 10 a of the light guide plate 10 and an area occupied bythe wavelength conversion layer 30 in the upper surface 10 a of thelight guide plate 10 may change in the first direction X. That is, anarea of the low refractive index pattern 20 is increased to increase atotal reflection ratio near the light incidence surface 10S1 at whichthe amount of guided light is sufficient, and an area of the wavelengthconversion layer 30 is increased to increase the amount of emitted lightnear the opposite surface 10S3 at which the amount of guided light islacking. As a result, the amount of light emitted toward the uppersurface 10 a of the light guide plate 10 near the light incidencesurface 10S1 becomes similar to the amount of light emitted toward theupper surface 10 a of the light guide plate 10 near the opposite surface10S3, and thus, it is possible to improve luminance uniformity.

The wavelength conversion layer 30 is disposed on the upper surface 20 aof the low refractive index pattern 20. A lower surface 30 b of thewavelength conversion layer 30 may be in contact with the upper surface20 a of the low refractive index pattern 20 and the upper surface 10 aof the light guide plate 10.

The wavelength conversion layer 30 converts the wavelength of at leastsome of incident light. The wavelength conversion layer 30 may include abinder layer and wavelength conversion particles dispersed in the binderlayer. The wavelength conversion layer 30 may further include scatteringparticles dispersed in the binder layer in addition to the wavelengthconversion particles.

The binder layer is a medium in which the wavelength conversionparticles are dispersed, and may be formed of various resin compositionsthat can be generally referred to as binders. However, the inventiveconcepts are not limited thereto, and, in this specification, a mediumin which the wavelength conversion particles and/or the scatteringparticles can be dispersed may be referred to as the “binder layer”regardless of its name, other additional functions, and elements.

The wavelength conversion particle is a particle that converts awavelength of incident light and may be, for example, a quantum dot(QD), a fluorescent material, or a phosphorescent material. The QD,which is an example of the wavelength conversion particle, will bedescribed in detail. The QD has a material with a crystalline structurewhich is several nanometers in size, is composed of hundreds tothousands of atoms, and shows a quantum confinement effect in which anenergy band gap increases due to a small size of a material. When lightwith a wavelength having higher energy than a band gap is incident onthe QD, the QD enters into an excited state by absorbing the light, andfalls to a ground state while emitting specific wavelength light. Theemitted specific wavelength light has a value corresponding to the bandgap. It is possible to adjust light-emitting characteristics of the QDdue to the quantum confinement effect by adjusting the size andcomposition of the QD.

For example, the QD may include at least one of group II-VI compounds,group II-V compounds, group III-VI compounds, group III-V compounds,group IV-VI compounds, group compounds, group II-IV-VI compounds, andgroup II-IV-V compounds.

The QD may include a core and a shell that coats the core. The core maybe at least one of, for example, CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, GaN,GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InP, InAs, InSb, SiC, Ca, Se, In,P, Fe, Pt, Ni, Co, Al, Ag, Au, Cu, FePt, Fe₂O₃, Fe₃O₄, Si, and Ge, butis not limited thereto. The shell may be at least one of, for example,ZnS, ZnSe, ZnTe, CdS, CdSe, CdTe, HgS, HgSe, HgTe, AlN, AlP, AlAs, AlSb,GaN, GaP, GaAs, GaSb, GaSe, InN, InP, InAs, InSb, TlN, TlP, TlAs, TlSb,PbS, PbSe, and PbTe, but is not limited thereto.

The wavelength conversion particle may include a plurality of wavelengthconversion particles capable of converting incident light into lightwith different wavelengths. For example, the wavelength conversionparticle may include a first wavelength conversion particle configuredto convert a specific wavelength of the incident light into a firstwavelength, and a second wavelength particle configured to convert aspecific wavelength of the incident light into a second wavelength. Forexample, light emitted from the light source 400 toward the wavelengthconversion particle may be light of a blue wavelength, the firstwavelength may be a green wavelength, and the second wavelength may be ared wavelength. For example, the blue wavelength may be a wavelengthhaving a peak between 420 nm and 470 nm, the green wavelength may be awavelength having a peak between 520 nm and 570 nm, and the redwavelength may be a wavelength having a peak between 620 nm and 670 nm.However, the blue, green, and red wavelengths are not limited to theabove example and should be understood to include all wavelength rangesrecognizable in the related art as blue, green, and red.

In this example, while blue light incident on the wavelength conversionlayer 30 passes through the wavelength conversion layer 30, a portion ofthe blue light may be incident on the first wavelength conversionparticle, converted into green wavelength light, and emitted; anotherportion thereof may be incident on the second wavelength conversionparticle, converted into red wavelength light, and emitted; and yetanother portion thereof may be emitted without being incident on thefirst and second wavelength conversion particles. Accordingly, the lightpassing through the wavelength conversion layer 30 may include all ofthe blue wavelength light, the green wavelength light, and the redwavelength light. It is possible to display white light or other lightby appropriately adjusting rates of light having different wavelengths.The light converted by the wavelength conversion layer 30 isconcentrated within a specific narrow wavelength region and has a sharpspectrum having a narrow half width. Accordingly, it is possible toimprove color representability by filtering light of the spectrum with acolor filter to represent colors.

Unlike the above example, incident light may be short wavelength lightsuch as ultraviolet rays, and three kinds of wavelength conversionparticles for converting a short wavelength into the blue wavelength,the green wavelength, and the red wavelength may be disposed in thewavelength conversion layer 30 to emit white light.

The wavelength conversion layer 30 may further include a scatteringparticle. The scattering particle is a non-quantum particle which has nowavelength conversion function. The scattering particle scattersincident light so that more incident light may be incident on theparticle conversion particle. Furthermore, the scattering particle mayuniformly control an emission angle of light for each wavelength. Indetail, the scattering particle has a scattering characteristic inwhich, when some incident light is incident on the wavelength conversionparticle, converted in wavelength, and then emitted, an emissiondirection thereof is random. When no scattering particle is present inthe wavelength conversion layer 30, the green wavelength and redwavelength emitted after the collision of incident light with thewavelength conversion particle have a scattering emissioncharacteristic, but the blue wavelength emitted when no collision of theincident light occurs with the wavelength conversion particle does nothave a scattering emission characteristic such that the amount ofemitted blue/green/red wavelength light may change depending on theemission angle. The scattering particle assigns the scattering emissioncharacteristic even to the blue wavelength being emitted withoutcollision with the wavelength conversion particle, thus similarlyadjusting the emission angle of light for each of the wavelengths. TiO₂,SiO₂, or the like may be used as the scattering particle.

A thickness of the wavelength conversion layer 30 may be greater thanthat of the low refractive index pattern 20. The wavelength conversionlayer 30 may have a thickness ranging from about 10 μm to about 50 μm.For example, the thickness of the wavelength conversion layer 30 may beabout 15 μm.

The wavelength conversion layer 30 may cover the upper surface 20 a ofthe low refractive index pattern 20, fill a through-hole H, and fullyoverlap the low refractive index pattern 20. The lower surface 30 b ofthe wavelength conversion layer 30 may be in direct contact with theupper surface 20 a of the low refractive index pattern 20. Also, thewavelength conversion layer 30 may be in direct contact with the uppersurface 10 a of the light guide plate 10 in a region in which thethrough-hole H is formed. In the region in which the light guide plate10 and the wavelength conversion layer 30 are in direct contact witheach other, light may not be totally reflected but may be emitted towardthe upper surface 10 a of the light guide plate 10 to enter thewavelength conversion layer 30.

For example, a side surface 30 s of the wavelength conversion layer 30may be aligned with the side surface 20 s of the low refractive indexpattern 20. The side surface 30 s of the wavelength conversion layer 30may have a smaller inclination angle than the side surface 20 s of thelow refractive index pattern 20. As will be described below, when thewavelength conversion layer 30 is formed by a method such as slitcoating, the side surface 30 s of the wavelength conversion layer 30,which is relatively thick, may have a smaller inclination angle than theside surface 20 s of the low refractive index pattern 20. However, theinventive concepts are not limited thereto, and the inclination angle ofthe side surface 30 s of the wavelength conversion layer 30 may besubstantially the same as or less than that of the side surface 20 s ofthe low refractive index pattern 20.

The wavelength conversion layer 30 may be formed by a coating method.For example, the wavelength conversion layer 30 may be formed byslit-coating a wavelength conversion composition onto the low refractiveindex pattern 20 and then drying and curing the wavelength conversioncomposition. However, the inventive concepts are not limited thereto,and various stacking methods, such as spin coating, roll coating, spraycoating, and inkjet coating, may be used.

The passivation layer 40 is disposed on the low refractive index pattern20 and the wavelength conversion layer 30. The passivation layer 40serves to prevent penetration of moisture and/or oxygen (hereinafterreferred to as “moisture/oxygen”). The passivation layer 40 may includean inorganic material. For example, the passivation layer 40 may includesilicon nitride, aluminum nitride, zirconium nitride, titanium nitride,hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide,titanium oxide, tin oxide, cerium oxide, silicon oxynitride, or ametallic thin film having light transmittance. For example, thepassivation layer 40 may include silicon nitride.

The passivation layer 40 may fully cover the low refractive indexpattern 20 and the wavelength conversion layer 30 at at least one sidesurface. For example, the passivation layer 40 may fully cover the lowrefractive index pattern 20 and the wavelength conversion layer 30 atall side surfaces, but the inventive concepts are not limited thereto.

The passivation layer 40 fully overlaps the wavelength conversion layer30 and covers an upper surface 30 a of the wavelength conversion layer30. Also, the passivation layer 40 extends outward to cover even theside surface 30 s of the wavelength conversion layer 30 and the sidesurface 20 s of the low refractive index pattern 20. The passivationlayer 40 may be in contact with the upper surface 30 a and the sidesurface 30 s of the wavelength conversion layer 30 and the side surface20 s of the low refractive index pattern 20. The passivation layer 40extends even to an edge of the upper surface 10 a of the light guideplate 10 exposed by the low refractive index pattern 20 so that aportion of the edge of the passivation layer 40 may be in direct contactwith the upper surface 10 a of the light guide plate 10. In an exemplaryembodiment, a side surface 40 s of the passivation layer 40 may bealigned with the side surface 40 s of the light guide plate 10. The sidesurface 40 s of the passivation layer 40 has an inclination anglegreater than that of the side surface 30 s of the wavelength conversionlayer 30. Furthermore, the side surface 40 s of the passivation layer 40may have an inclination angle greater than that of the side surface 20 sof the low refractive index pattern 20.

A thickness of the passivation layer 40 may be less than that of thewavelength conversion layer 30 and may be equal to or less than that ofthe low refractive index pattern 20. The thickness of the passivationlayer 40 may range from 0.1 μm to 2 μm. When the thickness of thepassivation layer 40 is greater than or equal to 0.1 μm, the passivationlayer 40 may exhibit a significant moisture/oxygen penetrationprevention function. When the thickness of the passivation layer 40 isgreater than or equal to 0.3 μm, the passivation layer 40 may have aneffective moisture/oxygen penetration prevention function. When thethickness of the passivation layer 40 is less than or equal to 2 μm,there are advantages in terms of thinning and transmittance. Forexample, the thickness of the passivation layer 40 may be about 0.4 μm.

The wavelength conversion layer 30, in particular, the wavelengthconversion particle included therein, is vulnerable to moisture/oxygen.A wavelength conversion film prevents penetration of moisture/oxygeninto the wavelength conversion layer by stacking a barrier film on anupper and lower surface of the wavelength conversion layer. However,according to this exemplary embodiment, the wavelength conversion layer30 is directly disposed without a barrier film, and thus, instead of thebarrier film, there is a need for a sealing structure configured toprotect the wavelength conversion layer 30. The sealing structure may beimplemented by the passivation layer 40 and the light guide plate 10.

Gates through which moisture may penetrate into the wavelengthconversion layer 30 are the upper surface 30 a, the side surface 30 s,and the lower surface 30 b of the wavelength conversion layer 30. Asdescribed above, the upper surface 30 a and the side surface 30 s of thewavelength conversion layer 30 are protected by being covered with thepassivation layer 40, and thus, it is possible to block or at leastreduce (hereinafter referred to as block/reduce) penetration ofmoisture/oxygen.

The lower surface 30 b of the wavelength conversion layer 30 is incontact with the upper surface 20 a of the low refractive index pattern20. In this case, when the low refractive index pattern 20 includes avoid or is made of an organic material, moisture may move into the lowrefractive index pattern 20, and thus moisture/oxygen may penetratethrough the lower surface 30 b thereof. However, according to thisexemplary embodiment, even the low refractive index pattern 20 may havea sealing structure, and thus it is possible to fundamentally block thepenetration of moisture/oxygen through the lower surface 30 b thereof.

In detail, the side surface 20 s of the low refractive index pattern 20is protected by being covered with the passivation layer 40, and thus,it is possible to block/reduce penetration of moisture/oxygen throughthe side surface 20 s thereof. Even when the low refractive indexpattern 20 protrudes farther than the wavelength conversion layer 30such that a portion of the upper surface 20 a is exposed, the exposedportion is protected by being covered with the passivation layer.Accordingly, even in this case, it is possible to block/reduce thepenetration of moisture/oxygen. The lower surface 20 b of the lowrefractive index pattern 20 is in contact with the light guide plate 10.When the light guide plate 10 is made of an inorganic material, such asglass, the light guide plate 10 can block/reduce the penetration ofmoisture/oxygen like the passivation layer 40. As a result, the surfaceof a stacked body of the low refractive index pattern 20 and thewavelength conversion layer 30 is surrounded and sealed by thepassivation layer 40 and the light guide plate 10. Accordingly, althougha moisture/oxygen moving path is provided inside the low refractiveindex pattern 20, it is possible to block/reduce the penetration ofmoisture/oxygen by the sealing structure, and thus, it is possible toprevent or at least alleviate deterioration of the wavelength conversionparticle due to moisture/oxygen.

The passivation layer 40 may be formed by a method such as deposition.For example, the passivation layer 40 may be formed on the light guideplate 10 on which the low refractive index pattern 20 and the wavelengthconversion layer 30 are sequentially formed by using a chemical vapordeposition method. However, the inventive concepts are not limitedthereto, and a physical vapor deposition, a sputtering method, an atomicdeposition, and other various stacking methods may be used.

As described above, the optical member 100 is a single integrated memberand may perform both a light guide function and a wavelength conversionfunction. The single integrated member may simplify a process ofassembling a display device. Also, it is possible to effectively achievetotal reflection on the upper surface 10 a of the light guide plate 10by placing the low refractive index pattern 20 on the upper surface 10 aof the light guide plate 10, and also it is possible to preventdeterioration of the wavelength conversion layer 30 by sealing the lowrefractive index pattern 20 and the wavelength conversion layer 30 withthe passivation layer 40 or the like.

Also, the wavelength conversion layer 30 and the sealing structure ofthe optical member 100 can reduce a manufacturing cost thereof anddecrease a thickness thereof in comparison to the case in which awavelength conversion film is provided as a separate film. For example,the wavelength conversion film is obtained by attaching a barrier filmto the upper and low portion of the wavelength conversion layer 30.However, the barrier film is expensive and also relatively thick (havinga thickness greater than or equal to 100 μm) and the total thickness ofthe wavelength conversion film reaches about 270 μm. Meanwhile,according to this exemplary embodiment, the low refractive index pattern20 may be formed to have a thickness of about 0.5 μm, and thepassivation layer 40 may be formed to have a thickness of about 0.4 μm.Accordingly, the total thickness of the optical member 100, except forthe light guide plate 10, may be maintained at about 16 μm, and thus, itis possible to decrease a thickness of a display device that employs theoptical member 100. Also, the manufacturing cost of the optical member100 may be controlled to be lower than that of the wavelength conversionfilm because an expensive barrier film can be omitted therefrom.

Other exemplary embodiments of the optical member will be describedbelow. In the following exemplary embodiments, descriptions of the sameconfigurations as those of the above-described exemplary embodiment willbe omitted or simplified, and differences therebetween will be mainlydescribed. The following drawings show arrangement/alignment relationsat one side surface of the optical member. However, the same structuremay be applied to a plurality of side surfaces or all side surfaces, andvarious side surface structures may be applied in combination. Eachstructure may be intentionally obtained and may also be unintentionallyobtained during a manufacturing process.

FIGS. 6 to 9 are plan views showing a light guide plate on which a lowrefractive index pattern is disposed according to various exemplaryembodiments. The exemplary embodiments of FIGS. 6 to 9 show that thelight guide plate may be formed in various shapes to change an area atwhich the low refractive index pattern is disposed.

FIG. 6 shows that through-holes H2 formed on a low refractive indexpattern 21 of an optical member 101 may have a constant size. That is,unlike the exemplary embodiment of FIG. 2, it is possible to adjust anarrangement density per unit area of the low refractive index pattern 21by changing an arrangement density of the through-holes H2 when thethrough-holes H2 of the low refractive index pattern 21 have a constantdiameter d. In detail, the number of through-holes H2 may graduallyincrease from the light incidence surface 10S1 of the light guide plate10 to the opposite surface 10S3. The through-holes H2 may be regularlyarranged in the first direction X and the second direction Y. However,the inventive concepts are not limited thereto, and the through-holes H2may be irregularly arranged. Even in this case, the arrangement densityincreases toward the opposite surface 10S3.

Separation distances Py between the through-holes H2 in the seconddirection Y may be uniform over the entirety of the light guide plate10. That is, the through-holes H2 may be sequentially aligned in thefirst direction X. On the other hand, the through-holes H2 may have afirst direction pitch Px gradually decreasing in the first direction X.The number of through-holes H2 per unit area near the light incidencesurface 10S1 may be smaller than the number of through-holes H2 per unitarea near the opposite surface 10S3.

As described above, the wavelength conversion layer 30 may be disposedin the through-holes H2. An area of the wavelength conversion layer 30in contact with the light guide plate 10 may change depending on thearrangement density of the through-holes H2. That is, a ratio of an areaoccupied by the wavelength conversion layer 30 to an area occupied bythe low refractive index pattern 20 near the light incidence surface10S1 may be greater than an area ratio near the opposite surface 10S3.As a result, the amount of light emitted toward the upper surface 10 aof the light guide plate 10 near the light incidence surface 10S1 may besimilar to the amount of light in the opposite surface 10S3, and thus,it is possible to improve luminance uniformity.

Referring to FIG. 7, a low refractive index pattern 22 of an opticalmember 102 may include a plurality of patterns. That is, since the lowrefractive index pattern 22 is composed of a plurality of patterns, itis possible to adjust an area ratio of the low refractive index pattern22 per unit area depending on a location thereof. The low refractiveindex patterns 20 and 21 of the optical members 100 and 101 shown inFIGS. 2 and 6 are different from that of the optical member 102 shown inFIG. 7 in that area ratios of the low refractive index patterns 20 and21 per unit area are adjusted by sizes and/or arrangements of thethrough-holes H1 and H2.

The plurality of patterns of the low refractive index pattern 22 may bearranged in the first direction X and the second direction Y. The uppersurface 10 a of the light guide plate 10, at which the low refractiveindex pattern 22 is not disposed, is exposed to the wavelengthconversion layer 30 so that the upper surface 10 a may be in directcontact with the wavelength conversion layer 30. That is, the region inwhich the low refractive index pattern 22 is not disposed may correspondto regions at which the through-holes H1 and H2 are arranged in the lowrefractive index patterns 20 and 21.

A planar shape of the low refractive index pattern 22 is notparticularly limited and may have a quadrangular shape. A planar area ofthe low refractive index pattern 22 may have the same size in the seconddirection Y. Conversely, the planar area of the low refractive indexpattern 22 may gradually decrease in the first direction X. As the areaof the low refractive index pattern 22 decreases, the exposed area ofthe upper surface 10 a of the light guide plate 10 increases. That is,an area occupied by the low refractive index pattern 22 in the uppersurface 10 a of the light guide plate 10 may gradually decrease in thefirst direction in inverse proportion with the area occupied by thewavelength conversion layer 30. Thus, near the opposite surface 10S3 inwhich the amount of guided light is small in comparison to the lightincidence surface 10S1, a ratio of the upper surface 10 a of the lightguide plate 10 in contact with the wavelength conversion layer 30 isrelatively high. As a result, even in this case, it is possible toimprove luminance uniformity.

Referring to FIG. 8, a low refractive index pattern 23 of an opticalmember 103 may include a plurality of patterns similar to the lowrefractive index pattern 22 of FIG. 7. However, the low refractive indexpattern 23 of FIG. 8 is different from the low refractive index pattern22 of FIG. 7, in which the plurality of patterns are irregularlyarranged in the second direction Y, in that the low refractive indexpattern 23 has a quadrangular prism shape continuously extending in thesecond direction Y.

The plurality of patterns of the low refractive index pattern 23 may bediscontinuously arranged in the first direction X while continuouslyextending in the second direction Y. For example, a long side of the lowrefractive index pattern 23 may be disposed in the second direction Yand a short side of the low refractive index pattern 23 may be disposedin the first direction X. A length of the long side of the lowrefractive index pattern 23 may be constant in the first direction X,and a length of the short side of the low refractive index pattern 23may gradually decrease in the first direction X. That is, a planar areaof the low refractive index pattern 23 may gradually decrease from thelight incidence surface 10S1 to the opposite surface 10S3 in the firstdirection X. Thus, the exposed area of the upper surface 10 a of thelight guide plate 10 increases in the first direction X, and an area ofthe upper surface 10 a of the light guide plate 10 in contact with thewavelength conversion layer 30 increases. As a result, the amount oflight emitted through the upper surface 10 a of the light guide plate 10near the opposite surface 10S3 increases, and thus it is possible toimprove luminance uniformity.

Referring to FIG. 9, a low refractive index pattern 24 of an opticalmember 104 may have a linear shape continuously extending in the firstdirection X. The low refractive index pattern 23 of FIG. 8 is differentfrom the low refractive index pattern 24 of FIG. 9 in that the lowrefractive index pattern 23 has a linear shape continuous extending inthe second direction Y.

A plurality of patterns of the low refractive index pattern 24 maycontinuously extend in the first direction X and may be arranged in thesecond direction Y. In an exemplary embodiment, a planar shape of thelow refractive index pattern 24 may have a triangular shape in which abase side thereof is disposed adjacent to the light incidence surface10S1. In another exemplary embodiment, the planar shape of the lowrefractive index pattern 24 may have a trapezoidal shape in which a longside thereof is disposed adjacent to the light incidence surface 10S1and a short side thereof is disposed adjacent to the opposite surface10S3. However, the shape of the low refractive index pattern 24 is notlimited to the above examples.

The low refractive index pattern 24 may have a width decreasing in thefirst direction X. That is, a planar area of the low refractive indexpattern 24 may decrease from the light incidence surface 10S1 to theopposite surface 10S3. Since the upper surface 10 a of the light guideplate 10 is exposed to the wavelength conversion layer 30 at a part atwhich the low refractive index pattern 24 is not disposed, a region inwhich the upper surface 10 a of the light guide plate 10 is exposed maygradually increase in the first direction X. Accordingly, the amount oflight emitted through the upper surface 10 a of the light guide plate 10increases from the light incidence surface 10S1 to the opposite surface10S3, and thus, it is possible to improve luminance uniformity.

As described above, the low refractive index patterns 20 and 21 may beformed so that an arrangement area decreases from the light incidencesurface 10S1 to the opposite surface 10S3 by forming the through-holesH1 and H2 or arranging a plurality of patterns having differentarrangement densities as the low refractive index patterns 22, 23, and24. Thus, near the opposite surface 10S3 of the light guide plate 10,the amount of light emitted toward the upper surface 10 a of the lightguide plate 10 may be greater than the amount of totally reflectedlight. However, the shapes and arrangement of the low refractive indexpatterns 21, 22, 23, and 24 are not limited to the above examples, andit is possible to adjust the arrangement areas of the refractivepatterns by various methods. The low refractive index patterns 20 to 24may be formed through a dry etching process, a printing method, or thelike. This will be described in detail below with reference to FIGS. 10to 13.

FIGS. 10 to 12 are sectional views schematically showing a method ofmanufacturing a low refractive index pattern according to an exemplaryembodiment. FIG. 13 is a sectional view schematically showing a methodof manufacturing a low refractive index pattern according to anotherexemplary embodiment.

Referring to FIG. 10, a low refractive index layer 20 m is formed on thelight guide plate 10. The low refractive index layer 20 m may be formedby a coating method. For example, the low refractive index layer 20 mmay be formed by coating the upper surface 10 a of the light guide plate10 with a composition for the low refractive index pattern 20 and dryingand curing the low refractive index layer composition. A method ofcoating with the composition for the low refractive index pattern 20 mayinclude slit coating, spin coating, roll coating, spray coating, andinkjet coating, but is not limited thereto. Other various stackingmethods may be used.

Subsequently, a photoresist film (not shown) is stacked on the entiretyof an upper surface of the low refractive index layer 20 m, and a mask Mis disposed on the photoresist film. The photoresist film is exposed tolight and developed using a developing solution to form a photoresistpattern PR.

Subsequently, as shown in FIG. 11, the low refractive index layer 20 mis patterned using the photoresist pattern PR as a mask to form a lowrefractive index layer 20P having patterns. For example, a dry etchingprocess may be used as a method of forming patterns in the lowrefractive index layer 20 m, but is not limited thereto.

A shape of the low refractive index layer 20P including the patterns maychange depending on a shape of the photoresist pattern PR. In anexemplary embodiment, the low refractive index layer 20P may includepatterns for the through-holes H1 and H2 shown in FIGS. 2 and 6. In thiscase, the photoresist pattern PR is disposed in a remaining region otherthan regions corresponding to the through-holes H1 and H2. That is, thephotoresist pattern PR may have a shape substantially covering onesurface of the low refractive index layer 20 m and having some exposedregions. The exposed regions of the photoresist pattern PR may beregions that become the through-holes H1 and H2.

In another exemplary embodiment, the low refractive index layer 20P maybe patterned in the shape of the plurality of low refractive indexpatterns 22, 23, and 24 shown in FIGS. 7 to 9. In this case, thephotoresist pattern PR may be formed only in some regions rather thansubstantially covering one surface of the low refractive index layer 20m. The regions in which the photoresist pattern PR is formed may beregions that become the low refractive index patterns 22, 23, and 24,and a region in which the photoresist pattern PR is not formed maycorrespond to a separation space between the low refractive indexpatterns 22, 23, and 24.

Subsequently, referring to FIG. 12, the photoresist pattern PR isremoved to complete the low refractive index patterns 20 to 24. The lowrefractive index patterns 20 to 24 include a pattern corresponding to anopening formed with the mask M.

Referring to FIG. 13, the low refractive index pattern 20 may be formedthrough a printing method. For example, the low refractive index pattern20 may be formed using a micro-gravure printing method, but is notlimited thereto.

A micro-gravure printing apparatus may include a reservoir, a doctorblade, a plate cylinder, and a blanket cylinder. Each of the platecylinder and the blanket cylinder have a cylinder shape which has asimilar length to the width of the light guide plate.

First, a plate cylinder including uneven patterns PP and EP is disposedsuch that the plate cylinder is partially immersed in a reservoirstoring the composition for the low refractive index pattern 20. Theuneven pattern may include an engraved pattern EP and a protrudingpattern PP that relatively protrudes. The engraved pattern EP provides aspace filled with the composition for the low refractive index pattern20, which becomes the low refractive index pattern 20. The engravedpattern EP has a shape corresponding to the low refractive index pattern20.

The engraved pattern is filled with the composition for the lowrefractive index pattern 20 when the plate cylinder rotates in acounter-clockwise direction. The doctor blade is disposed adjacent tothe plate cylinder and configured to remove the remaining compositionfor the low refractive index pattern 20 present in the plate cylinder sothat only the engraved pattern may be filled with the composition forthe low refractive index pattern.

In an exemplary embodiment, the protruding pattern PP may have a shapecorresponding to the through-holes H1 and H2, and the engraved patternEP may have a shape corresponding to the low refractive index patterns20 and 21. In this case, the low refractive index patterns 20 and 21including the through-holes H1 and H2 of FIGS. 2 and 6 may be formed inthe light guide plate 10.

In another exemplary embodiment, the engraved pattern EP may have ashape corresponding to the low refractive index patterns 22, 23, and 24,and the protruding pattern PP may have a shape corresponding to aseparation space between the low refractive index patterns 22, 23, and24. In this case, the low refractive index patterns 22, 23, and 24 ofFIGS. 7 to 9 may be formed on the light guide plate 10.

A circumference of the plate cylinder may be substantially the same as awidth from the light incidence surface 10S1 of the light guide plate 10to the opposite surface 10S2, and the uneven patterns PP and EP of thedoctor blade may be previously disposed to correspond to the entireshape of the low refractive index patterns 20 to 24. In this case, thelow refractive index patterns 20 to 24 may be formed by only onerotation of the doctor blade.

The blanket cylinder disposed in contact with the plate cylinder rotatesin a direction opposite that of the plate cylinder, for example, in aclockwise direction. The composition for the low refractive indexpattern 20 with which the engraved pattern of the plate cylinder isfilled is transferred to the blanket cylinder. A composition pattern forthe low refractive index pattern 20 transferred to the blanket cylindermay be pre-cured by UV emission.

The composition for the low refractive index pattern 20 transferred tothe blanket cylinder is transferred toward the light guide plate 10. Thecomposition for the low refractive index pattern 20 transferred to thelight guide plate 10 may be post-cured by heat application to completethe low refractive index patterns 20 to 24.

FIGS. 14 to 17 are sectional views of optical members according to stillother exemplary embodiments. The exemplary embodiments of FIGS. 14 to 17show that arrangement and alignment relationships of elements of theoptical member may be modified in various ways.

In an optical member 105 of FIG. 14, the passivation layer 40 may notfully cover the upper surface 10 a of the light guide plate 10 exposedby the low refractive index pattern 20. That is, unlike the exemplaryembodiment of FIG. 3, the side surface 40 s of the passivation layer 40may be recessed relative to the side surface 10S of the light guideplate 10 instead of being aligned with the side surface 10S of the lightguide plate 10. Such a structure may be formed when a deposition processis performed with a certain margin from the side surface 10S of thelight guide plate 10 to prevent a passivation material from beingdeposited on the side surface 10S of the light guide plate 10 when thepassivation layer 40 is formed. Even in this case, a sealing structuremay be maintained as long as the passivation layer 40 covers both thewavelength conversion layer 30 and the low refractive index pattern 20.

FIGS. 15 and 16 show that side surfaces 20 s of low refractive indexpatterns 20 of optical members 106 and 107 may not be aligned with sidesurfaces 30 s of wavelength conversion layers 30.

For example, as shown in FIG. 15, the side surface 30 s of thewavelength conversion layer 30 of the optical member 106 may be recessedrelative to the side surface 20 s of the low refractive index pattern20. That is, the side surface 20 s of the low refractive index pattern20 protrudes toward the outside relative to the side surface 30 s of thewavelength conversion layer 30. Such a structure may be obtained whenthe wavelength conversion layer 30 is formed with a certain margin fromthe side surface 10S of the low refractive index pattern 20 so that thewavelength conversion layer 30 may be stably disposed on the lowrefractive index pattern 20, which increases total reflectionefficiency. Even in this case, a sealing structure may be maintainedbecause the passivation layer 40 covers both the wavelength conversionlayer 30 and the low refractive index pattern 20.

In another example, as shown in FIG. 16, the side surface 30 s of thewavelength conversion layer 30 of the optical member 107 may protrudetoward the outside relative to the side surface 20 s of the lowrefractive index pattern 20. The protruding wavelength conversion layer30 may cover the side surface 20 s of the low refractive index pattern20, and a portion of the wavelength conversion layer 30 may be in directcontact with the upper surface 10 a of the light guide plate 10. Even inthis case, a sealing structure may be maintained because the passivationlayer 40 covers the side surface 30 s of the wavelength conversion layer30, and the lower surface 30 b of the protruding wavelength conversionlayer 30 is protected by the light guide plate 10.

FIG. 17 shows that the side surface 40 s of the passivation layer 40 ofan optical member 108 may protrude toward the outside relative to theside surface 10S of the light guide plate 10. For example, as shown inFIG. 17, the side surface 20 s of the low refractive index pattern 20may be aligned with the side surface 10S of the light guide plate 10,and the passivation layer 40 may extend toward the outside relative tothe side surface 20 s of the low refractive index pattern 20 to coverthe side surface 20 s of the low refractive index pattern 20. In anexemplary embodiment, the passivation layer 40 may even cover the sidesurface 10S of the light guide plate 10. Even in this case, a sealingstructure may be maintained as long as the passivation layer 40 coversboth the wavelength conversion layer 30 and the low refractive indexpattern 20. The exemplary embodiment of FIG. 17 may be advantageous inthat an effective light guide area of the light guide plate 10 ismaximized. Although not shown, even when the low refractive indexpattern 20 is recessed relative to the side surface 10S of the lightguide plate 10 as in the exemplary embodiment of FIG. 3, the passivationlayer 40 may protrude toward the outside relative to the side surface10S of the light guide plate 10.

FIG. 18 is a sectional view of an optical member according to stillanother exemplary embodiment.

An optical member 109 according to this exemplary embodiment isdifferent from that of the exemplary embodiment of FIG. 2 in that theoptical member 109 further includes a barrier layer 50 disposed on theupper surface 10 a of the light guide plate 10. In terms of arrangementof elements, the upper surface 10 a of the light guide plate 10 of FIG.2 may be replaced with an upper surface 50 a of the barrier layer 50 inthis exemplary embodiment.

More specifically with reference to FIG. 18, the barrier layer 50 isdisposed on the upper surface 10 a of the light guide plate 10, and thelow refractive index pattern 20, the wavelength conversion layer 30, andthe passivation layer 40 are sequentially stacked thereon. The barrierlayer 50 may fully cover the upper surface 10 a of the light guide plate10. The side surface 50 s of the barrier layer 50 may be aligned withthe side surface 10S of the light guide plate 10.

The low refractive index pattern 20 is formed to be in contact with theupper surface 50 a of the barrier layer 50. The low refractive indexpattern 20 includes the through-hole H1 to partially expose the uppersurface 50 a of the barrier layer 50. The exposed upper surface 50 a ofthe barrier layer 50 is in contact with the wavelength conversion layer30. That is, the lower surface 30 b of the wavelength conversion layer30 may be in direct contact with the low refractive index pattern 20 andthe barrier layer 50.

The low refractive index pattern 20 may partially expose an edge portionof the barrier layer 50. The wavelength conversion layer 30 is disposedon the low refractive index pattern 20, and the passivation layer 40fully covers the low refractive index pattern 20 and the wavelengthconversion layer 30. The passivation layer 40 fully overlaps thewavelength conversion layer 30 and extends outward to cover the sidesurface 30 s of the wavelength conversion layer 30 and the side surface20 s of the low refractive index pattern 20. The passivation layer 40even extends to an edge of the upper surface 50 a of the barrier layer50 exposed by the low refractive index pattern 20 so that a portion ofthe edge of the passivation layer 40 may be in direct contact with theupper surface 50 a of the barrier layer 50.

Similar to the passivation layer 40, the barrier layer 50 serves toprevent penetration of moisture and/or oxygen (hereinafter referred toas “moisture/oxygen”). The barrier layer 50 may include an inorganicmaterial. For example, the barrier layer 50 may include silicon nitride,aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride,tantalum nitride, silicon oxide, aluminum oxide, titanium oxide, tinoxide, cerium oxide, silicon oxynitride, or a metallic thin film havinglight transmittance. The barrier layer 50 may be made of the samematerial as that of the passivation layer 40, but is not limitedthereto. The barrier layer 50 may be formed by a deposition method suchas a chemical vapor deposition method.

The barrier layer 50 may have a thickness similar to that of thepassivation layer 40. For example, the thickness of the barrier layer 50may range from 0.1 μm to 2 μm.

The barrier layer 50 may have substantially the same refractive index asthe light guide plate 10 to perform a smooth light guiding function ofthe optical member 109. Alternatively, the barrier layer 50 may have adifferent refractive index from the light guide plate 10.

For example, when the refractive index of the barrier layer 50 is thesame as that of the light guide plate 10, a boundary between the lightguide plate 10 and the barrier layer 50 may not be recognized as aninterface. Thus, a propagation direction of light entering the boundarydoes not change. Accordingly, the light guide plate 10 and the barrierlayer 50 may perform substantially the same light guiding function asthe light guide plate 10 of FIG. 2.

When the refractive index of the barrier layer 50 is greater than thatof the light guide plate 10, an emission angle decreases at theinterface while a refractive index difference between the barrier layer50 and the light guide plate 10 increases. Thus, total reflection mayeffectively occur at the interface between the barrier layer 50 and thelow refractive index pattern 20.

When the refractive index of the barrier layer 50 is lower than therefractive index of the light guide plate 10, an emission angleincreases while some light is totally reflected at a correspondinginterface, and thus, it is possible to maintain maximum reflectionefficiency.

As another way to maintain light guide characteristics similar to thosein the exemplary embodiment of FIG. 2, the thickness of the barrierlayer 50 may be formed to be smaller than visible light wavelengths. Forexample, when the thickness of the barrier layer 50 is less than orequal to 0.4 μm, for example, is set in the range of 0.1 μm to 0.4 μm,an effective optical interface is not formed between the light guideplate 10 and the barrier layer 50 and between the barrier layer 50 andthe low refractive index pattern 20, and thus, the same light guidecharacteristics as shown in FIG. 2 may be exhibited regardless of therefractive index of the barrier layer 50. Even in consideration of themoisture/oxygen penetration prevention performance, the thickness of thebarrier layer 50 may be described in the range of 0.3 μm to 0.4 μm.

As described above, according to this exemplary embodiment, a sealingstructure of the wavelength conversion layer 30 may be implemented bythe passivation layer 40 and the barrier layer 50. Accordingly, evenwhen the moisture/oxygen penetration prevention function of the lightguide plate 10 is insufficient, it is possible for the barrier layer 50to effectively prevent the penetration of moisture/oxygen. In thisregard, the degree of freedom in which the elements of the light guideplate 10 can be selected may increase. For example, even when a polymerresin, such as a polymethylmethacrylate (PMMA) resin, a polycarbonate(PC) resin, and an acrylic resin, is used as the light guide plate 10instead of an inorganic material such as glass, it is possible toprevent the penetration of moisture/oxygen due to the barrier layer 50such that deterioration of the wavelength conversion layer 30 isprevented.

FIG. 19 is a sectional view of an optical member according to stillanother exemplary embodiment.

An optical member 110 of FIG. 19 is illustrated as being disposedadjacent to the side surfaces 10S1 and 10S3 of both long sides of thelight guide plate 10. In this case, both of the side surfaces 10S1 and10S3 of the light guide plate 10 are light incidence surfaces.

Both of the side surfaces 10S1 and 10S3 of the light guide plate 10 areadjacent to the light source 400 such that the amount of guided light issufficient and the amount of guided light is relatively insufficient inthe central portion of the light guide plate 10. The low refractiveindex pattern 20 may be disposed such that an area occupied by the lowrefractive index pattern 20 per unit area gradually decreases toward thecentral portion of the light guide plate 10. A planar area of thethrough-holes H1 may increase toward the central portion of the lightguide plate 10. In other words, a ratio of the area occupied by the lowrefractive index pattern 20 to an area occupied by the wavelengthconversion layer 30 in the upper surface 10 a of the light guide plate10 may be smaller in the central portion than in both of the sidesurfaces 10S1 and 10S3 of the light guide plate 10.

Thus, since the area occupied by the low refractive index pattern 20 islarge near the light incidence surfaces 10S1 and 10S3 of the light guideplate 10, the amount of totally reflected light may be larger than theamount of light emitted toward the upper surface 10 a of the light guideplate 10. On the other hand, since the area occupied by the lowrefractive index pattern 20 is small in the central portion of the lightguide plate 10, the amount of light emitted toward the upper surface 10a of the light guide plate 10 may be larger than the amount of totallyreflected light. Thus, the amount of guided light is sufficient andtotal reflection efficiency is high near the light incidence surfaces10S1 and 10S3 of the light guide plate 10 while the amount of guidedlight is sufficient and the amount of emitted light is large in thecentral portion of the light guide plate 10. Accordingly, the totalamount of light emitted through the upper surface 10 a of the lightguide plate 10 near the light incidence surfaces 10S1 and 10S3 maybecome similar to that in the central portion. As a result, it ispossible to improve luminance uniformity by adjusting a ratio of thearea occupied by the low refractive index pattern 20 per unit area.

FIGS. 20 and 21 are sectional views of optical members according tostill other embodiments. FIGS. 20 and 21 show that an integrated opticalfunction layer may be further included in optical members 111 and 112.The optical function layer is a layer for changing or controlling apropagation direction, a phase, a polarization state, or the like oflight. For example, the optical function layer may perform at least oneof refraction, condensation, diffusion, scattering, refractivepolarization, and phase delay of light. The optical function layer maybe a layer for performing the same optical function as that of a prismfilm, a diffusion film, a microlens film, a lenticular film, apolarizing film, a reflective polarizing film, a phase difference film,or the like provided as a separate film. The optical function layer mayinclude an optical pattern having a structured surface. The opticalpattern having a structured surface including an uneven surface. Asectional shape of the uneven surface may be, for example, a polygonsuch as a triangle and a trapezoid, a portion of a circle or an ellipse,or an amorphous random shape. The uneven surface may be a linear patternextending in one direction or an independent dot-type pattern. However,the present invention is not limited thereto, and an optical patternhaving a structured surface may have a flat surface such as a polarizingfilm or a reflective polarizing film.

The optical members 111 and 112 include an optical function layer 81disposed on the passivation layer 40. In the drawings, a prism patternis illustrated as the optical function layer 81, but a microlens or theabove-described other various optical function layers may be used. Theoptical function layer 81 may be made of a material having a higherrefractive index than the low refractive index pattern 20. Therefractive index of the optical function layer 81 may range from 1.5 to1.8, but is not limited thereto.

The optical function layer 81 may be disposed to overlap the wavelengthconversion layer 30 located thereunder. A side surface of the opticalfunction layer 81 may be aligned with or recessed relative to the sidesurface 30 s of the wavelength conversion layer 30.

In an exemplary embodiment, the optical function layer 81 may bedisposed to be in direct contact with the passivation layer 40, as shownin FIG. 20.

In another exemplary embodiment, the optical function layer 81 may bedisposed on the passivation layer 40, as shown in FIG. 21, and a bondinglayer 85 may be disposed therebetween. The bonding layer 85 may be madeof an adhesive material or a viscous material. As another example, thebonding layer 85 may be made of a double-sided tape. As still anotherexample, the bonding layer 85 may be made of a low refractive materialexemplified as a constituent material of the above-described lowrefractive index pattern 20. The bonding layer 85 may be made of thesame material as that of the low refractive index pattern 20. When thebonding layer 85 is made of the low refractive material, an opticalinterface is formed between the passivation layer 40 and the bondinglayer 85 and between the bonding layer 85 and the optical function layer81, and thus, light modulation such as refraction and reflection may beperformed.

FIGS. 22 and 23 are sectional views of optical members according tostill another embodiment. FIGS. 22 and 23 show that, in optical members113 and 114, the low refractive index pattern 20, the wavelengthconversion layer 30, and the passivation layer 40 may be disposed on thelower surface 10 b of the light guide plate 10.

The detailed shapes and arrangements of the low refractive index pattern20, the wavelength conversion layer 30, and the passivation layer 40 ofthe optical members 100 to 111 of FIGS. 1 to 21 may be applicable asdetailed shapes and arrangement of the low refractive index pattern 20,the wavelength conversion layer 30, and the passivation layer 40. Thatis, even when the low refractive index pattern 20 is disposed on thelower surface 10 b of the light guide plate 10, a ratio of an areaoccupied by the low refractive index pattern 20 per unit area maygradually decrease from the light incidence surface 10S1 to the oppositesurface 10S3. In this case, the amount of light emitted through thelower surface 10 b of the light guide plate 10 may increase from thelight incidence surface 10S1 to the opposite surface 10S3. When thewavelength conversion layer 30 is disposed on the lower surface 10 b ofthe light guide plate 10, color uniformity may increase.

In detail, light traveling toward the opposite surface 10S3 due to beingtotal reflected in the light guide plate 10 may be emitted toward thewavelength conversion layer 30 through the lower surface 10 b of thelight guide plate 10 at a plane on which the low refractive indexpattern 20 is not disposed. As described above, the wavelengthconversion layer 30 may include a wavelength conversion particle and ascattering particle. The wavelength conversion particle and thescattering particle have scattering characteristics in which lightpassed through the particles is emitted in a random direction. Greenwavelength light and red wavelength light passed through the wavelengthconversion particle and blue wavelength light passed through only thescattering particle are scattered and emitted in random directions. Thescattered green wavelength light, red wavelength light, and bluewavelength light may be appropriately mixed to display white light asemitted light. The probability of the green wavelength light, redwavelength light, and blue wavelength light being mixed increases as adistance from the scatting point increases, and thus the greenwavelength light, red wavelength light, and blue wavelength light may beappropriately mixed to display the white light as the emitted light suchthat uniform mixing may be achieved. That is, light is observed as amore uniform color in a direction away from the wavelength conversionlayer 30. Accordingly, as a distance between the wavelength conversionlayer 30 and a display panel 300 increases, a more uniform color may beobserved from the display panel 300 and color uniformity may increase.

The upper surface 10 a of the light guide plate 10 may be exposed by anair layer. However, as shown in FIG. 23, the optical function layer 81may be disposed thereon with the bonding layer 85 made of the lowrefractive material being interposed therebetween. In this case, theupper surface 10 a of the light guide plate 10 may form an opticalinterface together with the bonding layer 85 having a low refractiveindex, and thus effective total reflection may be achieved on the uppersurface 10 a of the light guide plate 10.

The above-described optical members 100 to 114 according to the variousexemplary embodiments may be applied to a display device, a lightingdevice, or the like. Exemplary embodiments of a display device includingthe optical member will be described in detail below.

FIG. 24 is a sectional view of a display device according to anexemplary embodiment.

Referring to FIG. 24, a display device 1000 includes a light source 400,an optical member 100 disposed along an emission path of the lightsource 400, and a display panel 300 disposed on of the optical member100.

All of the optical members 100 to 112 according to the above-describedexemplary embodiments may be used as the optical member. FIG. 24illustrates the case in which the optical member 100 of FIG. 2 is used.

The light source 400 is disposed at one side of the optical member 100.The light source 400 may be disposed adjacent to a light incidencesurface 10S1 of a light guide plate 10 of the optical member 100. Thelight source 400 may include a plurality of point light sources or linelight sources. Each of the point light sources may be a light emittingdiode (LED) light source 410. The plurality of LED light sources 410 maybe mounted on a printed circuit board 420. The LED light sources 410 mayemit blue wavelength light.

In an exemplary embodiment, the LED light source 410 may be aside-emitting LED configured to emit light from a side surface thereof,as shown in FIG. 24. In this case, the printed circuit board 420 may bedisposed on a bottom surface 510 of a housing 500. Although not shown,in another exemplary embodiment, the LED light source 410 may be atop-emitting LED configured to emit light upward. In this case, theprinted circuit board 420 may be disposed on a side wall 520 of thehousing 500.

The blue wavelength light emitted from the LED light source 410 isincident on the light guide plate 10 of the optical member 100. Thelight guide plate 10 of the optical member 100 guides light and emitsthe guided light through the upper surface 10 a or a lower surface 10 bof the light guide plate 10. A wavelength conversion layer 30 of theoptical member 100 converts a portion of the blue wavelength lightincident on the light guide plate 10 into light having otherwavelengths, for example, green wavelength light and red wavelengthlight. The converted green wavelength light and red wavelength light andunconverted blue wavelength light are emitted outward and provided tothe display panel 300.

The display device 1000 may further include a reflective member 250disposed under the optical member 100. The reflective member 250 mayinclude a reflective film or a reflective coating layer. The reflectivemember 250 reflects light emitted from the lower surface 10 b of thelight guide plate 10 of the optical member 100 and allows the reflectedlight to reenter the light guide plate 10.

The display panel 300 may be disposed on the optical member 100. Thedisplay panel 300 may receive light from the optical member 100 anddisplay the received light on a screen thereof. Examples of alight-receiving display panel configured to receive light and displaythe received light on a screen thereof may include a liquid crystaldisplay panel, an electrophoretic panel, and the like. The liquidcrystal display panel will be described as the display panel, but is notlimited thereto. Other various light-receiving display panels may beused.

The display panel 300 may include a first substrate 310, a secondsubstrate 320 facing the first substrate 310, and a liquid crystal layer(not shown) disposed between the first substrate 310 and the secondsubstrate 320. The first substrate 310 and the second substrate 320overlap each other. In an exemplary embodiment, any one of thesubstrates may be larger than the other substrate to protrude toward theoutside relative to the other substrate. FIG. 24 shows that the secondsubstrate 320, which is located at an upper portion, is larger andprotrudes from a side surface in which the light source 400 is disposed.A protruding region of the second substrate 320 may provide a space onwhich a driving chip or an external circuit board is mounted. Unlike theillustrated example, the first substrate 310, which is located at alower portion, may be larger than the second substrate 320 to protrudeoutward. An area of the display panel 300 at which the first substrate310 overlaps the second substrate 320 other than the protruding regionmay be substantially aligned with the side surface 10S of the lightguide plate 10 of the optical member 100.

The optical member 100 may be combined with the display panel 300through a module bonding member 610. The module bonding member 610 maybe formed in the shape of a planar quadrangular frame. The modulebonding member 610 may be located at an edge portion of each of thedisplay panel 300 and the optical member 100.

In an exemplary embodiment, a lower surface of the module bonding member610 may be disposed on the passivation layer 40. The lower surface ofthe module bonding member 610 may be disposed on the passivation layer40 to overlap an upper surface 30 a of the wavelength conversion layer30 but not a side surface 30 s thereof.

The module bonding member 610 may include a polymer resin, an adhesivetape, a viscous tape, or the like. The module bonding member 610 mayperform a light transmission blocking function by including a lightabsorption material, such as a black pigment or dye, or by including areflective material.

The display device 1000 may further include the housing 500. The housing500 has one open surface and includes the bottom surface 510 and theside wall 520 connected with the bottom surface 510. The light source400, an attaching body of the optical member 100/display panel 300, andthe reflective member 250 may be housed in a space defined by the bottomsurface 510 and the side wall 520. The light source 400, the reflectivemember 250, and the attaching body of the optical member 100/displaypanel 300 may be disposed on the bottom surface 510 of the housing 500.The side wall 520 of the housing 500 may have substantially the sameheight as the attaching body of the optical member 100/display panel 300located inside the housing 500. The display panel 300 may be disposedadjacent to the top of the side wall of the housing 500, and the displaypanel 300 and the housing 500 may be combined with each other by thehousing bonding member 620. The housing bonding member 620 may be formedin the shape of a planar quadrangular frame. The housing bonding member620 may include a polymer resin, an adhesive tape, a viscous tape, orthe like.

The display device 1000 may further include at least one optical film200. The at least one optical film 200 may be housed in a space disposedbetween the optical member 100 and the display panel 300 and surroundedby the module bonding member 610. A side surface of the at least oneoptical film 200 may be in contact with and attached to an inner surfaceof the module bonding member 610. FIG. 24 illustrates the case in whichthe optical film 200 is spaced apart from the optical member 100 and thedisplay panel 300, but separation spaces are not essentially required.

The optical film 200 may be a prism film, a diffusion film, a microlensfilm, a lenticular film, a polarizing film, a reflective polarizingfilm, a phase difference film, or the like. The display device 1000 mayinclude a plurality of the same type or different types of optical films200. When the plurality of optical films 200 are used, the optical films200 may be disposed to overlap each other, and side surfaces of theoptical films 200 may be in contact with and attached to the innersurface of the module bonding member 610. The optical films 200 may bespaced apart from each other, and an air layer may be disposedtherebetween.

In an exemplary embodiment, a composite film into which two or moreoptical function layers are integrated may be used as each of theoptical films 200. This will be described in detail with reference toFIG. 25.

FIG. 25 is a sectional view of an optical film according to an exemplaryembodiment. Referring to FIG. 25, an example optical film 200 mayinclude a first film 210, a second film 220, and a third film 230 whichare integrated.

The first film 210 may include a first member 211, a back-coating layer213 disposed on the bottom of the first member 211, and a first opticalpattern layer 212 disposed on top of the first member 211. When theoptical film 200 is spaced apart from the optical member 100, theback-coating layer 213 may be omitted.

The second film 220 may include a second member 221, a first bondingresin layer 223 disposed on the bottom of the second member 221, and asecond optical pattern layer 222 disposed on top of the second member221.

The third film 230 may include a third member 231, a second bondingresin layer 233 disposed on the bottom of the third member 231, and anoptical layer 232 disposed on top of the third member 231.

The first optical pattern layer 212 includes convex portions and concaveportions, and some of the convex portions are in contact with the firstbonding resin layer 223 or partially penetrate into and are combinedwith the first bonding resin layer 223. An air layer is disposed betweenthe first bonding resin layer 223 and the concave portions of the firstoptical pattern layer 212.

The second optical pattern layer 222 includes convex portions andconcave portions, and some of the convex portions are in contact withthe second bonding resin layer 233 or partially penetrate into and arecombined with the second bonding resin layer 233. An air layer isdisposed between the second bonding resin layer 233 and the concaveportions of the second optical pattern layer 222.

For example, the first optical pattern layer 212 may be a microlenspattern layer or a diffusion layer, the second optical pattern layer 222may be a prism pattern layer, and the optical layer 232 of the thirdfilm 230 is a reflective polarizing layer. In another example, the firstoptical pattern layer 212 is a prism pattern layer, the second opticalpattern layer 222 is a prism pattern layer (crossing the prism patternof the first optical pattern layer in an extending direction), and theoptical layer 232 of the third film 230 is a reflective polarizinglayer. In the exemplary embodiments, the third member 231 of the thirdfilm 230 may be omitted, and the second bonding resin layer 233 may bedisposed on the bottom of the optical layer 232. In addition, othervarious optical function layers may be used as the first optical patternlayer 212, the second optical pattern layer 222, and the optical layer232. Also, two films or four or more films may be integrated and used.

When the optical members 111, 112, and 114 including an integratedoptical function layer are used as an optical member like in theembodiments of FIG. 20, 21, or 23, all or some of the optical films 200that perform duplicated optical functions may be omitted.

FIG. 26 is a sectional view of a display device according to anotherexemplary embodiment.

FIG. 26 shows that the optical member 113 of FIG. 22 may be applied to adisplay device 1001. It should be appreciated that the optical member113 of FIG. 23 may be used.

A passivation layer 40 of the display device 1001 may be disposed to bein direct contact with a reflective member 250.

A region of a light source 400 from which light substantially originatesmay be disposed to correspond to a light incidence surface 10S1 of alight guide plate 10. Since a low refractive index pattern 20, awavelength conversion layer 30, and the passivation layer 40 aredisposed on a lower surface 10 b of the light guide plate 10, thedisplay device 1001 may have a height increasing from a bottom surface510 of a housing 500 to the lower surface 10 b of the light guide plate10. As the light source 400, an LED light source 410 configured tosubstantially emit light may be disposed adjacent to the light incidencesurface 10S1 of the light guide plate 10 by adjusting a height of aprinted circuit board 420. Also, as shown in FIG. 26, the sum ofthicknesses of the low refractive index pattern 20, the wavelengthconversion layer 30, and the passivation layer 40 is illustrated asbeing similar to a thickness of the light guide plate 10 for convenienceof understanding. However, the thickness of the light guide plate 10 isactually in the range of several millimeters while the sum of thethicknesses of the low refractive index pattern 20, and the wavelengthconversion layer 30, and the passivation layer 40 is actually in therange of several micrometers. Accordingly, a position of the lowersurface 10 b of the light guide plate 10 does not significantly rise.

A module bonding member 610 may be combined with an upper surface 10 aof the light guide plate 10. In a region of the upper surface 10 a incontact with the module bonding member 610, total reflection efficiencyof the upper surface 10 a of the light guide plate 10 may decrease. Inthis case, the module bonding member 610 may perform the lighttransmission blocking function, as described above, to block lightemitted toward the upper surface 10 a of the light guide plate 10.

With the optical member according to exemplary embodiments, it ispossible to perform both a light guide function and a wavelengthconversion function by using a single integrated member, and it is alsopossible for a sealing structure to prevent deterioration of awavelength conversion layer. The single integrated member has arelatively small thickness, and thus, can simplify a process ofassembling a display device.

The advantageous effects of the present invention are not limited to theabove-description, and various other effects are included in thisspecification.

Although certain exemplary embodiments and implementations have beendescribed herein, other embodiments and modifications will be apparentfrom this description. Accordingly, the inventive concepts are notlimited to such embodiments, but rather to the broader scope of theappended claims and various obvious modifications and equivalentarrangements as would be apparent to a person of ordinary skill in theart.

What is claimed is:
 1. An optical member comprising: a light guide plateincluding a surface disposed on a plane defined by a first direction anda second direction crossing the first direction; a refractive patterndisposed on the surface of the light guide plate and including anopening for exposing the surface of the light guide plate; a wavelengthconversion layer disposed on the refractive pattern; and a passivationlayer disposed on the wavelength conversion layer and configured tocover an upper surface of the wavelength conversion layer, thepassivation layer overlapping the refractive pattern, wherein: therefractive pattern has a lower index of refraction than the light guideplate; and a ratio of an area occupied by the refractive pattern to anarea of the surface of the light guide plate decreases in the firstdirection.
 2. The optical member of claim 1, wherein: the refractivepattern comprises a plurality of particles and a matrix including anorganic material; and the plurality of particles are dispersed in thematrix.
 3. The optical member of claim 2, wherein: the refractivepattern further comprises a plurality of voids; and the matrix fullysurrounds each of the plurality of voids.
 4. The optical member of claim3, wherein a refractive index of one of the plurality of voids and arefractive index of one of the plurality of particles are different fromeach other.
 5. The optical member of claim 1, wherein the opening is athrough-hole extending through the refractive pattern in a thirddirection perpendicular to the surface of the light guide plate.
 6. Theoptical member of claim 5, further comprising a plurality of thethrough-holes, wherein the plurality of through-holes have anarrangement density gradually increasing in the first direction.
 7. Theoptical member of claim 5, further comprising a plurality of thethrough-holes having a planar area gradually increasing in the firstdirection.
 8. The optical member of claim 1, further comprising aplurality of the refractive patterns spaced apart from each other toform the opening.
 9. The optical member of claim 8, wherein each of theplurality of refractive patterns has a planar area gradually decreasingin the first direction.
 10. The optical member of claim 9, wherein thewavelength conversion layer has an area in contact with the surface ofthe light guide plate, and the area gradually increases in the firstdirection.
 11. The optical member of claim 1, wherein the light guideplate comprises an inorganic material.
 12. The optical member of claim11, wherein a difference between a refractive index of the light guideplate and a refractive index of the refractive pattern is 0.2 or more.13. The optical member of claim 12, wherein the wavelength conversionlayer has a higher refractive index than the refractive pattern.
 14. Anoptical member comprising: a light guide plate including a surface, afirst side surface crossing the surface, and a second surface oppositethe first side surface; a refractive pattern disposed on the surface ofthe light guide plate and comprising an opening for exposing the surfaceof the light guide plate; a wavelength conversion layer disposed on therefractive pattern; and a passivation layer disposed on the wavelengthconversion layer and covering an upper surface of the wavelengthconversion layer, the passivation layer overlapping the refractivepattern, wherein: the refractive pattern has a lower index of refractionthan the light guide plate; the refractive pattern further comprises aplurality of voids and a matrix including an organic material; and thematrix fully surrounds each of the plurality of voids.
 15. The opticalmember of claim 14, wherein a ratio of an area occupied by therefractive pattern to an area of the surface of the light guide platedecreases in a direction away from the second side surface.
 16. Theoptical member of claim 15, wherein the wavelength conversion layer hasa higher refractive index than the refractive pattern.
 17. A displaydevice comprising: an optical member comprising, a light guide plateincluding a light incidence surface; a refractive layer disposed on thelight guide plate and having a lower index of refraction than the lightguide plate; a wavelength conversion layer disposed on the refractivelayer; and a passivation layer disposed on the wavelength conversionlayer and covering an upper surface of the wavelength conversion layer,the passivation layer overlapping the refractive layer; a light sourcedisposed at a side of the light incidence surface of the light guideplate; and a display panel disposed on the optical member, wherein therefractive layer comprises patterns, and an area in which the refractivelayer is disposed decreases in a direction away from the light incidencesurface.
 18. The display device of claim 17, further comprising areflective member disposed under the optical member, wherein thewavelength conversion layer is disposed between the light guide plateand the display panel.
 19. The display device of claim 17, furthercomprising a reflective member disposed under the optical member,wherein the wavelength conversion layer is disposed between the lightguide plate and the reflective member.